1. Field of the Invention
The present invention relates to a cholesteric liquid-crystal mixture, a film, a selective reflector, a laminate and a laminated glass.
2. Background Art
A laminated glass with a heat-shielding film sandwiched between two glass sheets is used for windshields of automobiles and for windowpanes of buildings. The heat-shielding film for use in these applications is desired to be flat and hazeless and have good visibility.
As the heat-shielding film, known is one that comprises a liquid-crystal film formed by fixing a cholesteric liquid-crystal phase on a support. The liquid-crystal film of the type may be formed, for example, by applying a coating liquid that contains a polymerizable cholesteric liquid-crystal compound onto a support and drying it thereon, followed by polymerization to thereby fix the cholesteric liquid-crystal layer. Here, there often occurs a problem of solid deposition that contains the liquid-crystal compound during coating and drying. Solid deposition that contains a liquid-crystal compound brings about a trouble of optical unevenness of the obtained heat-shielding film, and is therefore desired to be solved.
On the other hand, in addition to such a single type of liquid-crystal compound, there is known a liquid-crystal mixture that further contains, as mixed therein as a second liquid-crystal compound, a monomer or a liquid crystal that exhibits liquid crystallinity after polymerized, and contains, as further added thereto, a horizontal alignment agent, a polymerization initiator, a chiral agent and the like (see Patent Literatures 1 and 2). In these references, there is disclosed a liquid-crystal mixture that comprises liquid-crystal compounds each satisfying the general formula (Ia) and the general formula (Ib) described therein. In addition, these references describe, as a method for producing such liquid-crystal compounds, a method of reacting specific compounds to give a mixture of one type of a liquid-crystal compound having two polymerizable groups, two types of liquid-crystal compounds each having one polymerizable group and one type of a liquid-crystal compound not having a polymerizable group, or that is, such four different types of liquid-crystal compounds in total, for example, in Examples in Patent Literature 1.